A patient presents to the emergency center with a 6-hour history of fever to 38.9°C (102°F). Her mother reports that the patient appeared to be feeling poorly, that she had been eating less than normal, and that she vomited once. About 2 hours prior to arrival at the ER, the mother states that she noted a few purple spots scattered about the body on the patient, especially on the buttocks and legs. On the 30-minute ride to the ER, the purple areas spread rapidly and became coalesced in areas, and the patient is now obtunded. Which of the following is the most likely diagnosis?
a) Meningococcemia
b) Rocky Mountain spotted fever
c) Henoch-Schönlein purpura
d) Idiopathic thrombocytopenic purpura